Experimental study on the effect of micro-texture on EHL point contact film thickness subject to sliding conditions.

Abstract

Processing texture over contact pair surfaces can improve friction performance in interacting engineering systems. In this paper, micro-dimple textures with various parameter were processed on steel ball’s surface by using a femtosecond laser. Then the EHL (elastohydrodynamic lubrica-tion) oil film thickness was measured on an optical ball-on-disc tribometer subjected to pure sliding conditions. The effects of sliding velocity, load, dimple location and dimple depth on the film thickness of EHL were analyzed. This showed that dimple affected the pressure distribution in the contact area, and in turn affected the local film thickness distribution. The phenomenon of local film thickness increasing occurred under pure sliding conditions between the dimple and outlet of the contact region, while film thickness reduction region formed from the dimple to the entrance of the contact area and both sides of the dimple edge. Velocity and applied load potentially affect the film thickness distribution as well. The film thickness increasing region became larger while the film reduction area became smaller with increasing sliding velocity. The increase in load results in a negative effect on the increase of film thickness. This study could provide a reference for wear reduction design for point contact.